초록 ▼

The invention relates to a double-fed asynchronous generator, which is provided with a slipring rotor (1b), and to a method for its operation. In the normal manner, the asynchronous generator has a machine-side converter (5) and a network-side converter (6). According to the invention, the asynchron

The invention relates to a double-fed asynchronous generator, which is provided with a slipring rotor (1b), and to a method for its operation. In the normal manner, the asynchronous generator has a machine-side converter (5) and a network-side converter (6). According to the invention, the asynchronous generator is designed to supply short-circuit power in that at least one machine-side rotor current (iRM) is maintained in the event of a short circuit, in order to allow the formation of a stator-side short-circuit current. In order that inherent short-circuit currents in sensitive components of the converters (5, 6) are nevertheless avoided, at least the machine-side rotor current (iRM) is maintained in such a way that the actual rotor current (iRMact) in the event of a short circuit is used as the new nominal value in a control apparatus for the asynchronous generator.

대표청구항 ▼

1. A method for operating a double-fed asynchronous generator comprising a stator (1a) and a slipring rotor (1b); the method includes the following steps: Connect the stator (1a) to a power supply network (3), mechanically connect the rotor (1b) to a drive (11, 12), electrically couple the rotor (1b

1. A method for operating a double-fed asynchronous generator comprising a stator (1a) and a slipring rotor (1b); the method includes the following steps: Connect the stator (1a) to a power supply network (3), mechanically connect the rotor (1b) to a drive (11, 12), electrically couple the rotor (1b) via a machine-side converter and a power supply-side converter (5,6) to the network (3), monitor the network (3) to detect short-circuit current, supply a field-oriented current to the rotor (1b) at a frequency that substantially corresponds to the difference between the electrical network frequency and a mechanical frequency derived from the drive RPM, and regulate the machine-side rotor current, at the least, by determining the actual values (iRMist) of the machine-side rotor current (iRM) and adjusting them to setpoint values that are selected depending on desired operating conditions, wherein,if short circuits are detected in the network (3), the actual value (iRMist) of the machine-side rotor current (iRM) present at that time is detected, retained (frozen), and used in place of the selected setpoint values to regulate the machine-side rotor current, and therefore the stator (1a) delivers short-circuit current to the network (3). 2. The method as recited in claim 1, whereinthe machine-side rotor current (iRM), with all three phases, is transformed into a rotating coordinate system, forming q-axis currents and direct-axis currents (iRMq, iRMd), and the machine-side rotor current (iRM) is retained (frozen) by using the q-axis current (iRMq). 3. The method as recited in claim 1, wherein,if a short circuit occurs, the power supply-side rotor current (iRN) is likewise regulated, by detecting actual values (iRNist) of the power supply-side rotor current (iRN), recording (freezing) them, and using them in place of selected setpoint values (iRNsoll) to regulate the power supply-side rotor current. 4. The method as recited in claim 1, whereinthe retained (frozen) actual values that are used for regulation if a short circuit occurs are modified using correction values (±kiq, ±kid) which are derived from the total current (iG) of the generator (1). 5. The method as recited in claim 1, whereinthe retained (frozen) actual values that are used for regulation if a short circuit occurs are modified using correction values (±kiq, ±kid) which are derived from the total output (PG, QG) of the generator (1). 6. The method as recited in claim 1, whereinthe retained (frozen) state of the actual values is maintained for a preselected length of time. 7. A double-fed asynchronous generator, comprising: a stator (1a) that may be connected directly to a power supply network (3), a slipring rotor (1b) that is coupled mechanically to a drive (11, 12), and electrically to the network (3) via a machine-side converter and a power supply-side converter (5, 6), a means (30) which is connected to a switching device (25) for detecting short-circuit currents in the network (3), and a regulating circuit for performing the field-oriented regulation of the rotor-side converter (5) in such a manner that the rotor (1b) is always supplied with a current, the frequency of which substantially corresponds to the difference between the electrical power frequency and a mechanical frequency derived from the drive RPM, in which case the regulating circuit includes an actual value transmitter (19) for transmitting actual values (iRM) of at least one machine-side rotor current (iRM), and a setpoint value transmitter (17) for transmitting setpoint values—which are selected depending on desired operating conditions—for the machine-side rotor current (iRM), whereinthe switching device (25) is connected to the setpoint value transmitter (17) and the actual value transmitter (19) in such a manner that, if a short circuit occurs, the setpoint value transmitter (17) is separated from the regulating circuit and, instead, the actual value of the machine-side rotor current (iRM) that is currently present is retained (frozen), and is used as the new setpoint value, and therefore the stator (1a) may deliver short-circuit current to the network (3). 8. The double-fed asynchronous generator as recited in claim 7, whereinoutputs (19a, 19b) of the actual value transmitter (19) are connected to means (42 through 45) for modifying the actual values using correction values (±kiq, ±kid). 9. The double-fed asynchronous generator as recited in claim 7, whereinoutputs (28a, 19b) of the actual value transmitter (28) are connected to means (46 through 49) for modifying the actual values using correction values (±kiq, ±kid). 10. The double-fed asynchronous generator as recited in claim 7, whereinit is a component of a wind power station. 11. A double-fed asynchronous generator, whereinit includes a measuring device (26) that is connected to the actual value transmitter (19), and an output device (28) which is connected to the former and is used for actual values of the machine-side rotor current that are determined if a short circuit occurs, and the switching device (25) may be switched between the setpoint value transmitter (17) and the output device (28).